Meeting Abstract

S6.10  Tuesday, Jan. 5  Seasonal interactions and carry-over effects: understanding the biology of migratory organisms within the context of the annual cycle MARRA, P.P.; Smithsonian Institution marrap@si.edu

Migratory birds spend different parts of the annual cycle in geographically disparate places. The conditions and selective pressures at winter locations are likely to affect individual performance during the breeding season, and vice versa. This simple fact has important implications for the ecology, evolution, and conservation of migratory birds. Such inter-seasonal effects are poorly understood within most avian migration systems, in large part because it has been difficult to determine the connections between specific summer and winter populations. Stable isotopes have contributed enormously to our ability to link events in the annual cycle and research in my lab has begun to uncover the ecological and evolutionary significance of these connections. For example, because migratory organisms spend different parts of the annual cycle in geographically (and ecologically) separated locations, the dynamics of summer populations are likely to be strongly influenced by events on the wintering grounds and vice versa. Simple mathematical models illustrate the effects of density-dependence on population dynamics. Events on wintering grounds are also likely affect both arrival time and body condition of individual birds on the breeding grounds, and these parameters are likely to have important consequences for breeding behaviour, natal dispersal and annual survival. In this talk, I will describe through many of these specific examples how understanding seasonal interactions, carry-over effects and migratory connectivity is essential to our basic understanding of migratory bird biology. Finally, I will emphasize how it is essential to study biological phenomena in the context of the entire annual cycle.